Funds are sought to support establishment of a program of research directed to understanding of the origin and role of brain peptides in behavioral and physical disease. Endorphins have been implicated as involved in manifestation of depression, schizophrenia and in pain perception. We will evaluate the value of nonhuman primates as models for investigation of normal levels of endorphins in the CSF, and attempt to modify those levels by dexamethazone and metyrapone administration. A technique for chronic catheterization of the lateral ventricle of the chimpanzee will be developed and tested. An RIA for endorphin will be set up in the Yerkes Primate Center using available reagents, and we will attempt to produce antisera for such an assay which are superior to those commercially available.